Now we have useful brush - Elastic Deform
I found - it works like Proportional Edit Mode.
It will be great to have same option as Conncected Only!
May be it already is?
Yes. It already exists. The brush works with Topology Auto-Masking option.
Connected Only option is there to make a difference between parts of geometry.
What you are showing in video is not related to this option because there is only one part.
So, what you are talking about is really just the falloff of proportional edit tool.
So, if I am right ; question would be : how to control how far effect of brush goes ?
There is a Falloff panel in Brush properties. There is no a global radius limit exposed, here.
Fall Off is proportional to brush radius and other settings strength, hardness, fall off type. Settings that can be affected by pressure of stylus and amplitude of movement.
Result of brush stroke is beautiful and coherent because effect is propagated according to situation and is not fixed.
But contrary to proportional edit tool, you have ability to create a custom curve to control falloff.
So, you should be able to obtain desired result by using a brush with a lower radius, an higher strength and another FallOff Curve.
But if you don’t succeed to obtain desired result after simple tweaks, you can be very precised by creating a mask.
You can use shift A or Shift Alt A to quickly create a mask from cursor position. And you can smooth it, grow it, shrink it using A pie-menu.
That is relatively quick.
Sorry, this is dont solve a subject of the topic